Overhead door



Sept'G, 1938. H B LEWS 2,129,221

* OVERHEAD Doon Filed Feb. 12, 1934 2 Sheets-Sheet l [/v WSN roe: Hon/ard @.Le Wis,

W A Tron/ww sept. 6, .1938.

H. B. I Ewls OVERHEAD DOOR 2 Sheets-Sheet 2 Filed Feb. 12; 1954 Patented` 6, 1938 UNITED STATES PATENT OFFICE OVERHEAD DOOR Howard B. Lewis, Losl Angeles, Calif., assigner to Paton, Inc., Los Angeles, Calif., a corporation of California Application February 12, 1934, serial No. mais `8Claims.

The invention relates primarily to a simple counterbalance for an eccentrically mounted weight, and relates secondarily to a counterbalanced door embodying my new counterbalance.

Although there are many uses for the counterbalance, I shall, for the purpose of simplifying the disclosure of my invention, conne the clis- The doors swung on vertical hinges require space into which they may be swung into open position, and where sliding doors are employed, space must be provided for them when they are moved into open position. If a' door opening is equipped with a pair of door 'members adapted to overlap when one of the door members is open, the entire door area cannot be open at one time. O ver-l head doors, in addition tol other disadvantages .operated and which may be made in a single unit for a door opening of practically any width, the

' invention is of such simplicity that the cost of manufacture and installation of doorsis maintained at a It is an object of the invention to provide for use in doors ofthe character herein disclosed, and for other purposes, a simple formof counterbalance wherein, by use of springs, the door or other swingably mounted weight may be perfectly counterbalanced in all positions of rotation relative to the axis on which it is swingable.

A further object of the invention is to provide a door of the above character which may be easily adjusted to proper closing position after the installation of the parts thereof, and having asimple spring counterbalance means, the effect of which relative to the opening and closing movement of the door may be varied or adjustedl to suit requirements or individual preference.

VIt is a further object of the invention to provide a counterbalance means for a weight which .is rotatable around an eccentric axis, comprising (Cl. 2li- 16) force along a :hordal line extending from a movable point associated with the weight so as to rotate around a center of rotation to a stationary point which is in a position of commotion with the movable point when the center ci' gravity of the weight is disposed vertically above the axis v of rotation of the weight.

Further objects and advantages of the invention will be brought out in the following part of the speciication.

Referring to the drawings, which are for illustrative purposes only,

Fig. 1 is a longitudinally, vertically sectioned view showing an embodiment of `the invention employed as a door in a garage. the door being shown in partly raised position.

Fig. 2 is an enlarged fragmentary viewshowing the door of Fig. 1 in closed position. Fig. 3 is a longitudinally sectioned view taken as indicated by the line 3 3 of Fig. 2.

Fig. 4 is an enlarged fragmentary sectional view on a plane represented by the line 4 4 of Fig. 3.

Fig. 5 is a fragmentary section on a plane represented by the line 5-.5 of Fig. 4.

Fig. 6 is a force-diagram illustrating the operation of the counterbalance means involved in the structure shown in Figs. 1 to 5,.

Fig. 7 is a vertically sectioned view showing an alternative form of counterbalance structure involving my invention."

Fig. 8 is a sectional view showing the door of Fig. 'l in raised position.

' Fig. 9 is an enlarged perspective detail taken as indicated' by the arrow 9 of Fig. 7.

Fig. 10 is a perspective view showing a manner `in which a single spring may be connected so as to counterbalance bothends of a door in accordance with my invention.

Fig. 11 is a vertically cross sectioned view showing a form of the invention in which the door is pivotally attached to swingable supporting arms and is guided by means of a link during its movement between raised and lowered positions.

Fig. 12 is a vertically sectioned view showing a form of the invention in which the upper portion of the door is guided so as to travel in a horizontal plane as it is swung between raised andlowered positions.

Fig. 13 is an enlarged fragmentary section on a plane represented by the line i3-I3 of Fig. 12.

In Fig. 1 I show a garage I5 having a doorway or door opening Il of a size to permit passage of a vehicle, such as an automobile I1. For closing the opening I6 a door I8 is provided, this door being shown in open position in Fig. 1 and in closed position in Figs. 2 and 3. The door I8, as shown, is of a size to ll the width of the opening I6 and is of such height that the upper edge 20 thereof nearly reaches the wall edge 2I dening the upper limit of the opening I6. To illl the space22 between the edges 20 and 2I, a cover strip 23 may be secured to the wall edge 2 I. Projecting across the back of the door on opposite sides of a centrall horizontal plane are members 24, the ends 25 of which project beyond the sides 26 of the door I8 and extend across the inner faces of the front walls 21 of the garage I5. Secured to the ends of the members 25 are arms 28 which extend perpendicularly to the vertical plane of the door I8 and also horizontally when the door is closed, as shown in Fig. 2.

The arms 28 may be made of light-weight steel channels 3l having inwardly extending lips 32, as

shown in Fig. 4. In the rearward end 33 of each channel 3l a slidable block 34 is placed, this block being engaged by a screw 35 which extends through a plate or cap 36 on the rearward extremity of the channel 3I. The block 34 has an opening 31 for receiving a pin 38 which projects into a boss 48 formed on a mounting plate 4I. As clearly shown in Fig. 3, a mounting plate for the pivot means provided by the pin 38 is mounted adjacent the rearward end 33 of each of the pair of arms 28 and on some stationary part of the garage structure, such as posts or side walls 42 of the garage I5. The arms 28 are of such length that the mounting plates 4I may be placed with their pins 38 spaced from the door opening a distance substantially .equal to, but slightly less than, half the height of the door. By operation of the screws 35, the blocks 34 may be adjusted to vary the effective lengths of the arms 28 and thereby easily andquickly adjust the door I8 to a desired position in the opening I6.

Ropes or cables 44 are secured at 45 to the outer portions of the forward ends of the arms 28 and are carried over pulleys 46 mounted above the pivots provided by the pins 38, the distance of each pulley from its corresponding pivot being substantially the same' as the distance from the points 45 to the pins 38, the result being that when the door I6 is in closed position, as shown in Fig. 2, the portion 41 of each cable 44 extends at an angle of 45 relative to horizontal or vertical or constitutes a chord of the 90 arc 48 transscribed by the movement of the point 45 between horizontal and vertical positions.

From the pulleys 46 rearward portions 50 of the cables 44 extend to pulling means 5I, each of which, as shown in Fig. 2, may` consist of a forward attachment plate `52 and a rearward attachment plate 53 with a complement of springs 54 connecting` therebetween. The attachment plates 52 are connected to the portions 50 of the cables 44. and the attachment plates 53 are secured to a stationary member of the garage. The pulling means 5I, acting through the cables 44, exert up- -ward forces for counterbalancing the weight of the door I8 and its attachment so that by lifting on the door when it is in the position shown in Fig. 2. it may be rotated through the dotted line position 55 of Fig. 1 to the raised position in which I it is shown in full lines in Fig. 1.

A `feature of my invention resides in the use of the counterbalance spring means 5I which exerts its force along a line constituting the chord of the arc 48 of the securement point or points 45 of the upwardly rotatable door structure or other rotatable weight similarly secured, and which spring is so proportioned and positioned that it will exert a zero pull when the point 45 is in the vertical plane A-A of Fig. 2, and exert a pull sufcient to counterbalance the weight of the door and its associated part when the point 45 is in any other position, such as inthe lowered position in which it is' shown in Fig. 2.

I have discovered a new mathematical relationship which is involved in the counterweight dlsclosed herein, which will be made clear from a consideration of Fig. 6 in which a weight W rotates on a radius r around a point O. The torque Tw of the weight W around O due to gravity on the Weight W swinging about O at the radius -r is expressed as follows:

Tw=Wr cos :c

A spring of force constant is attached to a stationary point A directly above 0 a distance 1' to pull the weight W toward A. The extension of the spring E is zero when r is vertical. The torque Ts around the point O due to the spring is W A T.= 1,-;E

Therefore,

l -cos 2(90--x)= T.=Wr cos x=Tw Consequently, the system is in equilibrium at all points of a complete revolution of W around O.

In the above manner any weight rotatably mounted, such as the door I8, may be counterbalanced by use of a spring connected so as to exert its force along a chord or path extending from the point 45 to a point above the axis of rotation of the weight. A single spring may be employed, or springs may be placed so as to operate in unison, the number of springs employed varying with the weight of the door. In Figs. 1 to 6 of the drawings I have shown a garage door I8 counterbalanced by separate spring means 5I mounted at opposite ends of the door, eachof the spring means substantially counterbalancing half the weight of the door. In the'diagramrnatic perspective view, Fig. 10, I show the manner in which a door I8' may be counterbalanced by use of a spring 5I through cables 44a and 44h which may be carried over systems of pulleys 55 to connect to the spring 5I.

In Figs. 7 and 8 I show an alternative form of my invention in which my new principle of counterbalancing by use of a spring is practically applied without the use of cables or pulleys. In Fig. 7 I show a door opening I 6a closed by a door GII mounted on the forward ends of arms, such as the arm 3|' which pivotally engages a supporting member'4l'. The arm 3l' has bracket plates of triangular form 6I and 62, as shown in Fig. 9. secured to its forward end, providing flanges 63 by which the-arm may be secured to members 24'A placed across the back of the door 60. The upper 7 series of spring connecting means therealong in.

the form of holes 65. IWhen the door 66 is swung into raised position, as shown in Fig. 8, the

plate or iiange 64 assumes a vertical position. From one of the holes 65 in the iiange 64 a tension spring 66 sextended to a stationary mounting plate.61 which is secured above and to the right of the flange 64 at approximately an angle of as shown in Fig. 8, and in such position of commotion with the flange 64 that the spring 66 will extend between theiiange 64 and a flange 6B of the plat`e 61 in substantially relaxed condi-` `spring may be used at one end of the door of sufiicient strength to counterbalancev the entire door'.

It will be noted that when the door is in lowered position, the member 6l extends horizontally and at an angle of 90 to the ange 68; therefore, by moving the ends of the spring 66 to different holes in the members 64 and 68, the pull oi. the spring when the door 60 is in lowered position may be varied.I In this form ofthe invention the ideal conditions disclosed in the form of the invention shown in Fig. 6 are not reached, but the results obtained are entirely practicable, and the equipment necessary for the practice of the invention in this form is very simple and relatively inexpensive. In this alternative form of the invention auxiliary springs 10 may be connected from eyes 1I on the corner of the bracket 62 to plates 13 mounted on the sides of walls 14 J in which the opening'of the door Ilia is formed.

When the Vdoor is in lowered position, the springs 10 exert upward forces t assist in initial upward movement of the door, and as the door swings into overhead position, as shown in Fig. 8, the springs 10 maylbe also placed under tension to assist in initiatingthe closing or lowering movement of the door. For operation of the'door, a strap 1I may be suspended from the inner face thereof by which the door maybe swung from overhead to lowered position, and a suitable hand grip 12' may be placed on the front face of the door :for

` to the end of the arm 16, as in the previous forms of the invention, but is pivotally secured so that it may rotateA on a horizontal axis defined by a horizontal pipe 18 which extends laterally from the outer end of the,arm 16 which is shown-as i being equipped with counterweight means consisting of a spring 66a which extends from a plate y 66a near the outer end of the Aarm 16 to a wall plate 61a. From a iitting lll near the upper edge of the door member 15 a bar or link Il is extended to a stationary pivot 62 disposed below thepivot point 11 of the arm 16. As the arm V1t 'swings from the horizontal position in whion it is sh'own in full lines in Fig. 11-to the raised position shown in dotted lines 83, the link 8i swings to a position indicatedin dotted lines 8l,- and the upper end of such link 8i passes rightwardly through an arc 85. In. this form of the invention the upper edge of the door does not swing through an arc concentric with the pivot point 11, such as the arc 86, but follows the atter arc 65, thereby reducing the head room required for the door. During' the movement of the door member 15 from lowered position, through an intermediate position such as indicated by the dotted lines 15a, to the raised position thereof indicated by the dotted lines 15b, the door member 15 rotates relative to the outer end of the arm 16, the bracket means 61 by which the door member 15 is secured to tl'e pipe 16 rotating on the pipe 18. In lowered position the door member 15 is substantially perpendicular to the arm 16 but is swung into an acute-angle position relative to the arm 16 as the door 15 and the arm 16 swing upwardly, the door 15 being returned to a perpendicular position relative to the arm 16 when fully raised position of the door is reached.

In Fig. 12 I show a form of the invention in which the head rooin required for the door is further reduced. In this form of the invention a door member. is rotatably secured by means of a bracket 81 to a horizontal pipe 18 mounted on the outer end of an arm 16 having a stationary pivot point 11. Near the upper edge of the door 90 a plate 9|, as shown in Fig. 13, is secured, this plate carrying a laterally extending arm 92 having engagement means such as a roller 93 which engages a horizontal slot 94 in a plate 95 adapted to be secured to a vertical wall member 9 6 parallel to the movement of the roller 93 as the door 90 is swung from lowered position, as shownin full lines in Fig.'12, to the raised position 'shown i in dotted lines 81. As the arm 16 moves upwardly through the dotted line position, the roller 93 moves horizontally and rearwardly in the guide means provided by the slot 94, this causing the door 90 to swing through a position indicated by the dotted 'lines |00 and on the pipe 18 into an angular position relative to the arm 16. When the door reaches its completely raised position in. dicated by the dotted lines 91, the arm 16, in vertical position indicated by the dotted lines l0i,is again in a position perpendicular to the door. In this form of the invention the weight of the door 9|! and its associated parts is counterbalanced by a spring 51a, one e'nd of which is connected to a stationary member 53a and the other end of which is connected at |03 to the arm 16 by means of a rope or cable a which extends over a sheave 46a mounted vertically above the pivot point 11.

Although I have herein shown and described my invention in simple and practical form, it is recoghired `that certain parts or elements thereof are representative of other parts, elements, or mechanisrns which may bejused in substantially the same manner to accomplish substantially the same results; therefore, it is to be understood that the invention is not to be limited to the details ldisclosed `herein but is to beaccorded the full scope of the following claims.

I claim as my invention:

1. In combination with a building structure having a wall providing a door opening:` .a door cooperable with said door opening; an arm ex-,

tending rearwardly from said door; pivot means at the rear end of said arm on which said arm may swing to carry said door toward a position above necting between said door and said arm so as to be rswung through an arc as said door is moved around said pivot means; a force exerting element connected to said attachment means and being positioned to exert a force substantially along a chord of said arc; a stationary member connected to said force exerting element, said stationary member being in such position that saidl force exerting element is substantially relaxed when said door is in a position above said pivot means, said force exerting element being'` having a-door opening: a rigid door cooperable with said door opening; a pair of arms extending rearwardly from said door;` pivot means at the rear ends of said arms on which said arms may swing to carry said door toward a position above said pivot means; members placed substantially in a vertical plane with said pivot means; force exerting means connected to the forward ends of said arms and being positioned so as to exert a force to swing said arms through an arc as said door is moved around said pivot means, said force exerting means including a spring deformed in proportion to the change in distance between said arms and said members as said arms are moved away from said members by rotation of said door, the weight on said pivot means progressively increasing as said arms are moved into conjunction with said pivot means; and means for varying the lengths of said arms so as to adjust said door rellative to a desired position in said door opening.

3. In combination with a4 building structure having a wall providing a door opening: a door cooperable with said door opening; a pair of channeled arms extending rearwardly from said door; pivot means at the rear of said arms on which said arms may swing to carry said door toward a' position above said pivot means; attachment means connecting between said door and said arms so as to be swung through an arc as said door ismoved around said pivot means; force exmen'ts connected "toi" said attachment means vand being positioned to exert a force substantially along a chord of said arc; stationary members connected to said force exerting elements, said stationary members being in such position that said force exerting elements are substantially relaxed when said door is in a position above said pivot means, said force exerting elements being adapted to exert a force to raise said door, the weight on said pivot means increasing as said arms are moved to a position in conjunctionv with said pivot means; block members slidably mounted on said arms; and means for adjusting said block members so as to 'change the pivotal axis of said pivot means relative to said arms.

4. In combination with a building structure having a wall providing a door opening: a door cooperable with said door opening; a pair of arms extending rearwardly from said door; block members slidably mounted on said arms; pivot means associated with said block members on which said arms may swing to carry said door toward a position above said pivot means; force exerting means connected to the forward ends of said arms and being positioned so as to exert a force to swing said arms through an arc as said door is moved around said pivot means; and means connected to said block members and adapted for adjustment to change the pivotal axis of said pivot means relative to said arms.

5. In combination with a building structure having a wallproviding a door opening: a door cooperable with said door opening; a pair of arms extending rearwardly from said door; block members slidably mounted on said arms; pivot means associated with said block members on which said arms may swing to carry said door toward a position above said pivot means; force exerting means connected to the forward ends of said arms and being positioned so as to exert a force to swing said arms through an arc as said door is moved around said pivot means; and screw elements associated with said block members and being adapted for adjustment to change the pivotal-axis of said pivot means relative to said arms.

6. In combination with a building structure having a door openingza door cooperable with said door opening; a pair of arms extending rearwardly from said door; block members slida- Ably mounted on said arms; pivot means associated with said block members on whichsaid arms may swing to carry said door toward a position above said pivot means; stationary members placed substantially in a verticalplane with said pivot means; force exerting means connected to the forward ends of said arms and being positioned-so as to exert a force to swing said arms through an arc as said door is moved around said pivot means, said force exerting means including springs deformed in proportion to the change in distance between said arms and said stationary members as said arms are moved away from said members by rotation of said door, the Weight on said pivot means progressively increasing as said arms are moved into conjunction with said pivot means; and means associated with said block members for varying the length of said arms so as to adjust said door relative to a desired position in said door opening.

7. In combination with a building structure having a door opening:y a door cooperable with said door opening; a pair of arms extending rearwardly from said door; block members slidably d mounted on said arms; pivot .means associated with said block members on which said arms may swing to carry said door toward a position above said pivot means;` stationary members placed substantially in a vertical plane with said pivot means; force exerting means connected to the forward ends of said arms and being positioned so as to exert a f orce to swing said arms through an arc as said door is moved around said pivot means, said force exerting means including springs deformed in proportion to the change in distance between said arms and said stationary members as said arms are moved away from said members by rotation of said door, the weight on said pivot means progressively increasing as said arms are moved into conjunction with said pivot means; and screws associated with said block members adapted for adjustment to vary the length of said arms so .as to centralize said door relative to said door opening.

8. A counterbalanced door of the character described, including: a door; van arm extending rearwardly from said door; pivot means at the rear end of said arm on which said arm may swing to carry said door toward a position above said pivot means, said arm being pivotally secured to `said door; an attachment means'connected to said door so as to be swung through an arc as said door is moved around said pivot means; a force exerting element connected 'to said attachment means and being positioned to exert a `force substantially along a chord of said arc; a stationary member connected to said force exerting element, said stationary member being in such position that said force exerting element is substantially relaxed when said doory is in a position above said pivot means, said force exerting element being adapted to exert a force to raise said door, which force varies substantially in proportion to the length of said chord; a link for guiding the door as it moves between relatively closed and open positions; means for pivotally securing one end of said link to said door;

and a stationary pivot means attached to the l other end oi said link.

v HOWARD B. LEWIS. 

